Thursday, March 29, 2018

Season 11 premier division, final results

Final crosstable after RR12

The premier league is over, Stockfish and Houdini will fight for the title in the superfinal, Fizbo and Ginkgo will be relegated to division 1 next season.

Komodo finished third, 3 points behind Houdini. Considering the 84 games each engine played this is not a large difference, but its losses to Houdini and Stockfish (five losses, one win in total) were the deciding factor.

The closest race was for 5th place, Andscacs after another weak RR score of 2/7 lost its place to Chiron (3.5/7).

The superfinal will consist of 100 games, 50 openings chosen by Jeroen Noomen. The time control will be 120+15, game duration will be close to 4 hours. Stockfish will be updated, Houdini will not. There's always some risk involved in updating the engine, hopefully there will not be serious bugs found during the games. Based on the premier division results (12 games, 11 draws, one win for Stockfish) the engines' strengths are very similar, and it is hard to say what the outcome will be.

A few interesting games

Fire - Ginkgo: After many early exchanges only QB vs QB were left on move 27. Fire had a better pawn structure, and after exchanging queens it had a pair of connected passers, enough for a win.

Fizbo - Fire: After move 14 the engines did not exchange pieces for a long while. Fizbo had a lot more space behind its pawns, and its eval was over 2, yet Fire seemed solid enough as the engines shuffled. They got to move 150 under time pressure when Fire took a rook for a knight. In the QRB vs QRR position Fire had only one pawn beyond the 6th rank. Fizbo's eval jumped as it forced a queen exchange on move 184. Fire realized it was losing, though it took a while for Fizbo to find the way to win. An unexpected result, Fire does not play well under time pressure.

Ginkgo - Komodo: The game was balanced until move 35 with most of the action on the queen side. Ginkgo grabbed a pawn, leaving its king and queen exposed to attacks. This allowed Komodo to gain the initiative, leading to a deadly attack on the white king and a win.

Stockfish - Ginkgo: Stockfish had an eval advantage after the start which increased gradually. Ginkgo chose to trade RB for Q and evals jumped. Ginkgo's rooks and bishops harrassed the white queen, but eventually Stockfish managed to trade pieces and reach a winning Q vs RB ending with 2 pawns up.

Komodo - Fizbo: Komodo took advantage of Fizbo's exposed king with not enough black pieces on the king side to develop a strong king side attack. Komodo drove the black king to the center and started to win material. The game was adjudicated in a QBN vs QN position, Komodo a pawn up.

Fire - Chiron: Fire was a pawn up with a small eval advantage after exchanging queens. Chiron allowed Fire to create a passer on the queen side while it created a passer on the king side. Chiron traded a rook for a bishop and in return got a second passer on the 2nd rank, but no further. Fire's rooks were too strong, after trading the advanced passers Fire's remaining pawns started to march, eventually forcing Chiron to lose a bishop and the game.

Andscacs - Komodo: Material was balanced when Komodo pushed its pawns on the queen side. Andscacs tried to counter on the king side, sacrificing a bishop for pawns it exposed the white king. Komodo defended carefully, giving back the material and trading down to a double rook ending. A queen side passer on the 2nd rank was enough for the win.

Houdini - Fizbo: The center was locked and Houdini a pawn up after opening the black king side. Evals were over 2 as Houdini moved its king to the queen side, apparently preparing for a king side attack which never started. Instead Houdini slowly strangled Fizbo, capturing a second pawn on the queen side. When the game was adjudicated Fizbo could not move without losing material.

Stockfish - Andscacs: Stockfish started with an eval advantage, its pieces had more space while Andscacs' pieces could hardly move. After exchanging queens Stockfish opened the king side and pushed a passer forward, Andscacs lost a knight to stop it. The game reached a RRB vs RR position with white passers advancing in the center, a win for Stockfish. After this loss Chiron and Andscacs have the same number of points with two games remaining.

Komodo - Fire: Komodo traded a rook and pawns for two knights early in the game. Fire was 3 pawns up after a few exchanges, the engines started to stabilize the pawns and shuffle from move 27. Evals started to jump suddenly on move 84, Fire probably blundered and Komodo saw a path to win. With 4 moves left on the 50-move counter Komodo forced a knight for rook trade, and then opened up the board and traded down to a won RN vs R position.

Andscacs - Houdini: Houdini's eval started to jump on move 26. It sacrificed a knight for pawns to open the king side and then concentrated forces to attack the white king. Andscacs gave a rook to clear the black queen side pawns, in the hope that its queen side passers will slow down the attack. Houdini traded down to a N vs R ending, the white pawns were easy targets, game over. After this Andscacs drops down to 6th place, 0.5 points behind Chiron.

Chiron - Fizbo: Chiron had an eval advantage from the start, it kept its king in the center and pushed pawns on the king side. Fizbo sacrificed a knight for pawns and after a series of exchanges both kings were exposed, Chiron's eval over 1.5. Fizbo's attack on the white king was not effective, Chiron created a passer on the queen side and exchanged pieces when possible. The game was adjudicated in a QRN vs QR position with a white pawn on the 7th rank. With the win Chiron will finish 5th, Andscacs can not close the gap in the remaining game.

Stockfish started with a significant eval advantage from the opening. For the first 25 moves Komodo held the position, keeping the evals close to 1. The king side looked like a fortress around the black king, on the queen side Komodo had a rook stuck in the corner, only good for protecting the a pawn.

Stockfish's eval started to increase a little, then the engines had a very long PV agreement which they started to play out. It appeared the game was heading towards a drawn RN vs RN ending.

Suddenly the evals jumped over 2. Both engines realized that by moving the knight to e3 on move 41 Stockfish could protect its king, keep the queens and force a rook exchange, leading to a QN vs QN ending.

Stockfish had checks available and it could avoid a Komodo counter attack on its king. Within a few moves Stockfish was a pawn up, the game was adjudicated before reaching a winning knight ending. This game was an excellent way to close the division.